Air-blast transformer.



E. R. -PEARSON.

AIR BLAST TRANSFORMEH. APPLICATION FILED AuG.21. 1915.

1,301,735. Patented Apr. 22, 1919.

4 I' j Inventor:

EdwnRPear-sorl b LJ His Jfttorngg.

v g' M' UNITED STATES PATENT OFFICE.

EDWIN R. PEARSON, OF PITTSFIELD, MASSACHUSETTS, ASSIG-NOR T0 GENERAL' ELECTRIC COMPANY, A CORPORATION 0F NEW YORK.

AIBfBLAs'r TRANSFORMER.

- Specicaton of Letters Patent.

Patented Apr. 22', 1919.

Application filed August 27, 1915. Serial No. 47,592.

To all whom it m ag/ concern Be it known that I, EnwiN R. PEARsoN, a citizen of the United States, residing at Pittsfield, county of Berkshire, State of Massachusetts. have invented certain new and useful Improvements in Air-Blast Transformers, of which the following is a specification. v

This invention relates to stationary transformers of large capacity, which are cooled by a forced air blast flowing through passages between the sections of the core and between the coils of the windings. The object of the invention is to. improve the details of construction of such a transformer, in order to simplify the construction and effect a more complete and thorough cooling of the parts. The features of noveltyvwill appear in the following specification and claims, taken in connection with the accompanying drawing, in which Figure 1 is a vertical central section of a transformer of the shell type embodying my invention; Fig. 2 is a vertical section on line 2-2, Fig. 1, in a. plane at right angles to Fig. 1. and Fig. 3 is a cross-section on the line 3 3, Fig. 1.

A strong rectangular base 4 supports the core 5 which is composed` as usual, of sheet metal laminations and for convenience is divided into two similar sections, placed side by side. In the longer legs of the laminations is a longitudinal slot, so that when the core is built up, these slots will register and form ducts 6, 6 extending vertically through each of the longer sides of each section of the core. A space 7 is left between the sections, forming a central duct between the two ducts 6 in the middle leg of the core.

The low tension coils 8 and the high tension coils 9 are thin flat structures and are spaced apart to afford vertical flues between adjacent coils. The coils are retained in position by grooves in the inner surface of upright outer walls 10 of insulating material which, with end walls 11, form a boxing inclosing the windings. Where they pass through the core the coils are supported in grooves in the inner walls 12. The distance between the walls 10 and 12 is not so wide as the openings in the laminations through which the coils pass, so that vertical ducts 13, 13 are left between the boxing and the adjacent edges of the laminations, the former outside and the latter inside. The low tension coils are separated from the high tension coils by upright partitions 14, which, together with the outer walls 10 and the end walls 11 of the `boxing project well above and below the top and bottom edges of the coils, and are extended across the middle leg of the core.

The space between the under side of this middle leg and the lower turns of the coils is partly filled by insulating material 15 and one or more thin plates 15 of such material, leaving a passage 16 throughthe coils beneath the core, said passage being open at each end. The coils are suspended on a block 17 of insulation which rests on a strong plate 18 which runs lengthwise of the upper side of the middle leg of the core, and is supported upon said core. A transverse passage .19 is formed in the middle leg of the core Just below the plate 17. and intersecting the vertical ducts 6 and 7 in said middle. leg.

The coils are kept apart by spacing strips 20, which extend midway between the walls 10 and 12 of the boxing. Those 'coming up through one side of the winding are preferably curved at the top toward those coming up through the other side.

The vertical ducts 6 in the outer legs of the core communicate with 'the interior of the base 1 at their lower ends; but their upper ends open into the atmosphere, as the core is not inclosed and the casing 21 is narrower than the base, and rests upon that part 'of the core legs inside of the ducts 6.

The air blown into the base by the usual blast. apparatus passes up through the ducts 6 in the outer core legs, through the ducts 13 between said legs and the outer walls 10 of the boxing, and through the spaces between the coils. The curved upper ends of the spacing strips 20 direct part of the air against the upper turns of the windings above the middle leg of the c ore. Air also enters at each end of the passage 16 and flows up through the ducts 6( in the middle leg of the core and through the ducts 13 between this 'core leg and the inner walls 12 of the boxing. At the top of these ducts it enters the intersecting passage 19, through which it passes to the middle duct 7, flowing down into this space and out at ends thereof; all as indicated by the arrows in Figs. 1 and 2. A plate 22 at the bottom of the space 7 prevents the air from escaping from the passage 16 directly into the duct 7.

The air for cooling the core bathes the edges of all the laminations at four points in each longer side of each section. This air passes up in vertical lines, over the outer legs of the core. For the inner leg, it is slightly diverted in order to enter the ends of the passage 16, and in entering the central space 7 it is deflected through the transverse passage 19 and reversed in direction to enter said space. The edges of the laminations, however, are exposed to the air at four points in each section of the middle leg of the core. The air for cooling the coils rises unobstructed through upright flues between the coils and within the boxing. It is en-4 tirely separated from the air that cools the core; the two columns uniting only at the top of the casing 21; some distance above the tops of the coils. It is thus possible to run the core at a higher temperature than the coils at normal full load; and even on an overloadthe coils will rarely exceed the core in temperature.

In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof; but I desire to have it understood that the apparatus shown is only illustrative, and that the two outer legs and a central leg with a vertical duct open at its sides dividing the central leg, said sections being formed with vertical ducts through the laminations, and coils on said central leg gdisposed in spaced relation to each other-'and to the core to provide vertical ducts between the coils and between the coils and core; transverse passagesvbeing provided adjacent the top andl bottom of said central leg, the bottom passage arranged to connect with the ducts through the laminations and with the ducts between the core and coils, the top passage arranged to connect with the said same ducts and with the vertical duct dividing the central leg.

2. An air blast transformer of the shell type having a core comprising laminated magnetic elements arranged to form outer and central legs with a vertical duct open at its sides in the middle of the central leg, and coils on said central leg disposed in spaced relation to each other and to the core to provide vertical ducts between the coils and between the coils and the central leg, said core and coils being arranged to provide transverse Ventilating passages adjacent the top and bottom of said central leg, thetop pas` sage connecting the ducts between the coils and central legs with the duct in the middle 'of the central leg,the bottom passage connecting the ducts between the coils themselves with the ducts between the coils and central leg. v

3. An air blasttransformer of the shell type having a core comprising laminated magnetic elements arranged to form outer and central legs with a vertical duct open at its sides in the middle of the central leg, and coils on said central leg disposed in spaced relation to each other, said core and coils being arranged to provide transverse ventilating passages adjacent the top and bottom of the central leg and other vertical ducts, the top passage connecting the said other ducts with the duct in the middle of the central leg, the bottom passage connect# ing said other ducts with the passages between the coils.

4. In an air blast transformer, the combination with a base, of uninclosed laminated core sections supported on said base provided with vertical air ducts in their outer legs, the lower ends communicating with the interior of said base, and a casing mounted upon said core sections inside the openings of said air ductswhereb the upper ends thereof conn'nunicate Wit the atmosphere outside the transformer.

In witness whereof, I have hereunto. set my hand this 23rd day of August, 1915.

EDWIN R. PEARSON. 

